Worksites, such as mines, landfills, quarries, excavation sites, etc., commonly have machines operating thereon to perform a variety of tasks. At a mining site, for example, a fleet of mining shovels and haul trucks may cooperate to remove material from various quarries and to transport the material to various dump sites. Communication networks have been provided to enable fleet communication on the worksite. A conventional worksite communication network includes a fleet of machines and a dispatch system which coordinates operations of the fleet to accomplish the task at hand. The fleet members may monitor their performance on the worksite, and may transmit performance data to the dispatch system. The dispatch system may, based on the performance data, monitor progress at the worksite and coordinate machine operations to efficiently accomplish the task. In addition, the fleet members may communicate with each other, such as to avoid collisions, to provide loading or dumping positioning information, or for other reasons.
Due to the nature of the worksite, however, it can be difficult to establish reliable communication networks. The movement of the fleet members, geographical obstacles, exposure to the elements, and other factors can degrade the integrity of signal transmissions. Accordingly, there is a need to provide reliable communication networks suitable for changing conditions on the worksite.
One such communication network is disclosed in U.S. Patent Application Publication No. 2005/0002354 by Kelly et al., published on Jan. 6, 2005 (the '354 publication). The '354 publication discloses an ad-hoc communication network whereby machines form sub-networks as they travel about the worksite and come within communication range of one another. Collectively, the sub-networks form an overall ad-hoc network that allows the machines to communicate with each other via intermediate nodes overlapped by two or more sub-networks.
While the communication network formed by the '354 publication may be advantageous because of its versatility, it may be unreliable in some ways. For example, a message transmitted on the network propagates from source to destination across the sub-networks, and between the sub-networks via the intermediate nodes. However, because the structure of the network continually changes with the movement of the machines, the path from a particular source to a particular destination may also continually change. Accordingly, traffic on the network is not structured or organized in any particular way to ensure reliability, because the network architecture is based entirely upon geographical location.
This disclosure is directed to overcoming one or more of the problems set forth above.